mpm: Make default clock/time source values state-less

Currently, the default clock/time source is whatever the user configured
in the last session.

This fixes the scenario were you have any MPM device and do this:

    $ benchmark_rate --args $args,clock_source=external

But whoops! You forgot to attach an external 10 MHz. PLL lock fails,
nothing works. No worries, you run it again:

    $ benchmark_rate --args $args

With the previous behaviour, this would retain the setting to
'external', because there's nothing to overwrite it. You would need to
append `clock_source=internal` to get a working device again. Calling
multi_usrp::set_clock_source("internal"), or a similar API call, might
not be sufficient because the PLL lock failure might crash the program
before updating the clock source is possible.

The problem with this is twofold:

- All non-MPM devices behave differently, i.e., they have a fixed
  default ('internal') which is always applied if no other option is
  given. This is an internal inconsistency.
- Some applications (like gr-uhd's GRC bindings) simply don't set
  a clock/time source when selecting a "default", or they try and update
  the clock/time source using the API calls.

Therefore, we align the behaviour of MPM devices with the other devices,
and fall back to an internal source if nothing else is provided.

4 files changed, 13 insertions, 13 deletions

diff --git a/mpm/python/usrp_mpm/periph_manager/e31x.py b/mpm/python/usrp_mpm/periph_manager/e31x.py
index 5a228d869..17a21d6e7 100644
--- a/mpm/python/usrp_mpm/periph_manager/e31x.py
+++ b/mpm/python/usrp_mpm/periph_manager/e31x.py
@@ -386,10 +386,9 @@ class e31x(ZynqComponents, PeriphManagerBase):
             self.log.warning(
                 "Cannot run init(), device was never fully initialized!")
             return False
-        if args.get("clock_source", "") != "":
-            self.set_clock_source(args.get("clock_source"))
-        if args.get("time_source", "") != "":
-            self.set_time_source(args.get("time_source"))
+        args = self._update_default_args(args)
+        self.set_clock_source(args.get("clock_source", E310_DEFAULT_CLOCK_SOURCE))
+        self.set_time_source(args.get("time_source", E310_DEFAULT_TIME_SOURCE))
         if "no_reload_fpga" in args:
             self._do_not_reload = \
                 str2bool(args.get("no_reload_fpga")) or args.get("no_reload_fpga") == ""
diff --git a/mpm/python/usrp_mpm/periph_manager/e320.py b/mpm/python/usrp_mpm/periph_manager/e320.py
index 2878fe2b5..f3a8da12d 100644
--- a/mpm/python/usrp_mpm/periph_manager/e320.py
+++ b/mpm/python/usrp_mpm/periph_manager/e320.py
@@ -298,10 +298,9 @@ class e320(ZynqComponents, PeriphManagerBase):
             self.log.warning(
                 "Cannot run init(), device was never fully initialized!")
             return False
-        if args.get("clock_source", "") != "":
-            self.set_clock_source(args.get("clock_source"))
-        if args.get("time_source", "") != "":
-            self.set_time_source(args.get("time_source"))
+        args = self._update_default_args(args)
+        self.set_clock_source(args.get("clock_source", E320_DEFAULT_CLOCK_SOURCE))
+        self.set_time_source(args.get("time_source", E320_DEFAULT_TIME_SOURCE))
         result = super(e320, self).init(args)
         for xport_mgr in itervalues(self._xport_mgrs):
             xport_mgr.init(args)
diff --git a/mpm/python/usrp_mpm/periph_manager/n3xx.py b/mpm/python/usrp_mpm/periph_manager/n3xx.py
index 2fbb12365..6800d356b 100644
--- a/mpm/python/usrp_mpm/periph_manager/n3xx.py
+++ b/mpm/python/usrp_mpm/periph_manager/n3xx.py
@@ -420,6 +420,7 @@ class n3xx(ZynqComponents, PeriphManagerBase):
             self.log.error(
                 "Cannot run init(), device was never fully initialized!")
             return False
+        args = self._update_default_args(args)
         # We need to disable the PPS out during clock and dboard initialization in order
         # to avoid glitches.
         self.enable_pps_out(False)
@@ -429,8 +430,8 @@ class n3xx(ZynqComponents, PeriphManagerBase):
         # properties should have been set to either the default values (first time
         # init() is run); or to the previous configured values (updated after a
         # successful clocking configuration).
-        args['clock_source'] = args.get('clock_source', self._clock_source)
-        args['time_source'] = args.get('time_source', self._time_source)
+        args['clock_source'] = args.get('clock_source', N3XX_DEFAULT_CLOCK_SOURCE)
+        args['time_source'] = args.get('time_source', N3XX_DEFAULT_TIME_SOURCE)
         self.set_sync_source(args)
         # Uh oh, some hard coded product-related info: The N300 has no LO
         # source connectors on the front panel, so we assume that if this was
diff --git a/mpm/python/usrp_mpm/periph_manager/x4xx.py b/mpm/python/usrp_mpm/periph_manager/x4xx.py
index 76c9e365d..7479874dc 100644
--- a/mpm/python/usrp_mpm/periph_manager/x4xx.py
+++ b/mpm/python/usrp_mpm/periph_manager/x4xx.py
@@ -631,6 +631,7 @@ class x4xx(ZynqComponents, PeriphManagerBase):
             self.log.warning(
                 "Cannot run init(), device was never fully initialized!")
             return False
+        args = self._update_default_args(args)
 
         # We need to disable the PPS out during clock and dboard initialization in order
         # to avoid glitches.
@@ -638,9 +639,9 @@ class x4xx(ZynqComponents, PeriphManagerBase):
             self._clocking_auxbrd.set_trig(False)
 
         # If the caller has not specified clock_source or time_source, set them
-        # to the values currently configured.
-        args['clock_source'] = args.get('clock_source', self._clk_mgr.get_clock_source())
-        args['time_source'] = args.get('time_source', self._clk_mgr.get_time_source())
+        # to the default values.
+        args['clock_source'] = args.get('clock_source', X400_DEFAULT_CLOCK_SOURCE)
+        args['time_source'] = args.get('time_source', X400_DEFAULT_TIME_SOURCE)
         self.set_sync_source(args)
 
         # If a Master Clock Rate was specified,